Development of the method of an electrohydrodynamic force effect on a boundary layer for active control of aerodynamic flows

The results of investigations on the possibility of an electrohydrodynamic force effect on a gas flow implemented with the help of a barrier discharge are presented. A new method of controlling the laminar flow around a base with suppression of instabilities of the incoming flow due to electrohydrodynamic force action on the boundary layer near the forward edge of a swept wing is proposed. An efficient multidischarge actuator system is developed and created for active control of aerodynamic flows with induced-air-flow characteristics exceeding the world analogues.     

Field-effect transistor structures on the basis of poly(3-hexylthiophene), fullerene derivatives [60]PCBM, [70]PCBM,and nickel nanoparticles

Organic field-effect transistor (OFET) structures with the active layers on the basis of composite films of semiconductor polymer poly(3-hexylthiophene) (P3HT), fullerene derivatives [60]PCBM, [70]PCBM, and nickel (Ni) nanoparticles are obtained, and their optical, electrical, and photoelectrical properties are studied. It is shown that introducing Ni nanoparticles into P3HT: [60]PCBM and P3HT: [70]PCBM films leads to an increase in the absorption and to quenching of photoluminescence of the composite in the 400–600 nm spectral band due to the plasmon effect. In P3HT: [60]PCBM: Ni and P3HT: [70]PCBM: Ni OFET structures at the P3HT: [60]PCBM and P3HT: [70]PCBM concentrations of ~1: 1 and Ni concentrations of ~3–5 wt %, current–voltage (I–V) characteristics typical of ambipolar OFETs with the dominant hole conduction are observed. The charge-carrier (hole) mobilities calculated from the I–V characteristic at V_G =–10 V were found to be ~0.46 cm²/(V s) for P3HT: [60]PCBM: Ni and ~4.7 cm²/(V s) for P3HT: [70]PCBM: Ni, which means that the mobility increases if [60]PCBM in the composition is replaced with [70]PCBM. The effect of light on the I–V characteristics of P3HT: [60]PCBM: Ni and P3HT: [70]PCBM: Ni OFETs is studied.     

Synthesis and Spin State of the Cobalt(II) Complexes with Substituted 2,6-Bis(pyrazol-3-yl)pyridine Ligands

Russian Journal of Coordination Chemistry - The direct template reactions afford the cobalt(II) complexes (I–III) with the hydroxy- and acetyl-substituted 2,6-bis(pyrazol-3-yl)pyridine...     

Specific features of dielectric response in PZT ferroelectric films

Crystallography Reports - Reverse dependences of the permittivity ε′(E =) of Pb(Ti0.45Zr0.53W0.01Cd0.01)O3 ferroelectric films prepared by high-frequency magnetron sputtering on a...     

Structural phase transitions in heteroepitaxial ferroelectric films

The changes in the structural—deformational characteristics occurring during the phase transitions in the crystal lattice of epitaxially grown thin (Ba,Sr)TiO₃ films on the (001) cleavage of MgO crystals have been studied. It is shown that microdeformations along the surface normal of the wall of a c-domain film increase with the temperature and attain maximum values in the vicinity of the phase transition. No decrease in the dimensions of the coherent-scattering regions was observed. The comparison of the deformation of the “average” lattice and microdeformations led to the assumption that the transition from the paraelectric to the ferroelectric phase is accompanied by the dislocation-induced formation of a dipole-glass-type intermediate phase at the temperatures exceeding that of the phase transition.     

On the question of the magnitude of day-night asymmetry for solar neutrinos

The effect of flavor day-night asymmetry is considered for solar neutrinos of energy about 1 MeV under the assumption that the electron-density distribution within the Earth is approximately piecewise continuous on the scale of the neutrino-oscillation length. In this approximation, the resulting asymmetry factor for beryllium neutrinos does not depend on the structure of the inner Earth’s layers or on the properties of the detector used. Its numerical estimate is on the order of ?4 × 10^?4, which is far beyond the reach of present-day experiments.     

Hot-wire method for measurements of turbulent mixing induced by Richtmyer-Meshkov instability in shock tube

A constant temperature hot-wire anemometry method is applied to the study of mixing zones induced by the interaction of a shock wave with Mach number 1.25 in air with air/helium (heavy/light), air/argon or air/krypton (light/heavy) initially plane interfaces. The single wire gauge is positioned at various locations along the shock tube axis. At the present stage of our investigation, although the analysis of the hot-wire signal is not achieved yet, we report the interesting concept of using hot-wire anemometry as a diagnostic method for shock tube studies of the Richtmyer-Meshkov instability. Based on this preliminary work, we discuss prospective experimental signal conversion, in order to provide some new results for this field of investigation, in particular for resolving characteristics of the turbulent mixing zone which is of most interest. Received 3 August 2000 / Accepted 15 February 2001